The present invention relates to a tire loading apparatus for a tire vulcanizing machine.
Hitherto a variety of tire loading apparatuses were proposed for charging a green tire into a molding die assembly on a tire vulcanizing machine. One of the conventional tire loading apparatuses is constructed in such a manner as to include a plurality of tire clamping shoes arranged radially relative to the center thereof, said tire clamping shoes being adapted to move outwardly or inwardly in the radial direction.
A drawback which is inherent to the conventional tire loading apparatus is, however, that it has a substantially reduced centering accuracy because a green tire to be vulcanized is manually charged onto a tire holding stand of the apparatus the loading operation and in case of a light weight type tire the upper side wall of the tire is deformed unsymmetrically relative to the lower one due to a reduced rigidity of the side wall when the green tire is firmly held in a horizontal posture along the tread portion thereof. Further, another drawback of the conventional loading apparatus is that there is a danger that a green tire will become deformed into a polygonal configuration due to an outwardly activated stretching force which is required for holding the green tire securely. One of the possible remedial measures for preventing unsymmetrical deformation of the upper side wall of the green tire is to increase the width of the tire clamping shoes. This proposal however, is impracticable because there is a certain restriction relative to radial displacement of the tire clamping shoes. In addition to this, another drawback of the conventional loading apparatus is that delicate adjustment is required for reduction of the stretching force given by the tire clamping shoes followed by downward displacement of the green tire in order to ensure that horizontal straightening is effected for the unsymmetrically deformed upper side wall of the green tire. Further, it is found that correct centering is not easy to achieve due to appreciable clearance in guide members for the tire clamping shoes and that no correct centering is ensured when the green tire is firmly held along the inner wall of the bead portion thereof with the tire clamping shoes radially displaced to the outermost position, resulting in elliptical deformation of the bead portion. Obviously, these drawbacks which are inherent to the conventional loading apparatus have an adverse effect on the quality of the tires which are manufactured in the vulcanizing machine.